Hibiscus plant named ‘DUP-BYR’

ABSTRACT

A new and distinct cultivar of  hibiscus  plant named ‘DUP-BYR’, characterized by exceedingly upright, sturdy growth habit appropriate for container production and culture freely flowering habit, and a double flower characterized by petals and petaloids having a body of lavender blue, and a margin of rose-purple.

Latin name of the genus and species: Hibiscus rosa-sinensis.

Variety denomination: ‘DUP-BYR’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar ofhibiscus, botanically known as Hibiscus rosa-sinensis and hereinafterreferred to by the cultivar name ‘DUP-BYR.’

Hibiscus have been the subject of human admiration for centuries. Whilethe ancestry of present rosa-sinensis hybrids is not precisely known,today's hybrids are thought to be the products of interspecific crossesinvolving Hawaiian, Polynesian and Asian species, among others, some ofwhich may no longer be found in the wild, if they are to be found atall. It is thought that the first hibiscus identified as a rosa-sinensiswas a double red form of uncertain origin found in cultivation in China,India and Polynesia, to be later introduced to Hawaii from Polynesia. Itis known to have been grown in Europe during the Victorian era.Eventually, it was introduced to the continental United States where itwas cultivated outdoors in the Deep South as well as in regions havingsubtropical or Mediterranean climates (Florida and Southern California,respectively). Indoor cultivation took place in the temperate regions ofthe U.S. It is speculated that the original rosa-sinensis is actually aspecies hybrid, possibly naturally arising, involving two or morespecies. Regardless, present day hybrids are descended from the originaldouble form, and are thought to include in their ancestry Hibiscusliliiflorus, H. arnottianus, H. schizopetalus, as well as other species,particularly those native to Hawaii.

Today, after decades of extensive hybridization, the moniker“rosa-sinensis” almost certainly denotes complex interspecific hybrids.Such hybrids are usually far removed from their species ancestors inform and color. Flowers characterized by spectacular size, colorintensity and, in the last several decades, ringed and spotted patternshave been produced by U.S. hybridizers in Louisiana, Florida, Hawaii,Texas and elsewhere. Other hotbeds of hibiscus-breeding activity includeAustralia, and more recently, Tahiti. Today's flowers are removed fromtheir species ancestors to such an extent that it is almost impossibleto unravel the species component contributions which comprise a modernhybrid hibiscus.

However, in the past, despite the fact that hybridization was givingrise to flowers of spectacular size and color intensity, very few if anyearly hybrids attracted the attention of large scale commercialpropagators. While the flowers were truly some of the most impressive inthe entire plant world, hybridizers had been selecting predominantly forbloom characteristics. As a result, many of these spectacular hybridswere weak plants which, even with the best care, were short-lived anddifficult to grow. The occasional production of a spectacular bloom wasenough to keep the interest of those truly dedicated to growingsomething rare and special, and thus new hybrids continued to beproduced by hobbyists with abundant passion and small amounts ofgreenhouse space. As a result, more breathtaking varieties were producedeach year, to be distributed via grafting among dedicated hobbyists,only to die out within a time span of 10 or 15 years. It should be notedthat the majority of the varieties introduced in the 1960's, 70's andeven many from the 1980's and 90's are likely to be lost to cultivation,if they are not already.

Progress toward the development of a plant which an average gardenercould easily grow and enjoy was slow to non-existent. Many varietieswere difficult to root from cuttings, and even if they did root, manyvarieties, when grown on their own roots, were extremely susceptible tofungal and bacterial root rots. Some grew acceptably only as graftedplants. However, grafted plants suffer from a serious disadvantage inthat the quality of the graft generally determines the quality of theplant, making the production of uniformly vigorous plants a difficulttask. Furthermore, after several years, it is common for grafted plantsto develop stresses at the graft union due to the unequal growth ratesof the rootstock and the scion. Such stresses can eventually lead toloss of vigor and death of the plant. Moreover, grafting does notcompletely cure the problem of root rot; surprisingly, the rootstock,when grafted to a root rot susceptible scion was generally still morelikely to suffer rot than a plant of the rootstock variety. For example,a plant of ‘Seminole Pink’ a garden variety commonly used as arootstock, is highly resistant to root rot. However, when ‘SeminolePink’ is used as a rootstock for ‘Romeo’ a modern hybrid which is proneto root rot, the grafted plant, while less susceptible than Romeo, ismore susceptible than a plant of Seminole Pink.

Perhaps the most detrimental disadvantage of grafted plants is theintroduction of viruses into the scion from the rootstock. Rootstockvarieties are almost invariably old garden varieties which, over theyears, have become infected with multiple viruses. While the performanceof such vigorous garden varieties may be largely unaffected by virusinfection, the hybrid scion of a grafted plant has generally beensignificantly less vigorous than the garden variety rootstock, and virusinfection from the rootstock resulted in a weak plant. The problem onlyincreased with successive generations of grafting, resulting in a rapidgeneral weakening of a given variety over time.

Because many hybrids are shy bloomers at best, the extra stresses due tovirus infection, grafting, low disease resistance, and the likegenerally gave sparse flower production, as well as a high number ofdeformed blooms. Furthermore, ordinary stresses such as over/underwatering and mite/insect pests resulted in a high perecentage of buddrop. The buds of large-flowered hybrids often take relatively longtimes to reach blooming stage, and it was not uncommon to wait withanticipation while a bud swelled day by day, only to be disappointedwhen the mature bud toppled from its pedicel on the day it was to open.

Moreover, because of hybridizer emphasis on the flower, the plant wasoften relatively slow growing and sparsely clothed in leaves. Suchplants usually do not attract purchasers as they do not have theappearance of garden-worthy specimens.

It has been noted in the industry that a hybrid hibiscus seems to sellonly when it is bearing a bloom. The practical effect of all of theabove-mentioned issues on a retail outlet is as follows. A garden centerwill order a number of plants. Many of the plants will arrive either inbloom or up to several days away from blooming. The blooming plants willgenerally sell the first day. On several subsequent days, new bloomswill open on the remaining plants, and some of them will sell as well.However, by the fourth or fifth day, the lack of perfect growingconditions begins to take is toll, and the plants begin to drop theirmost mature buds. From this point on, the plants essentially sit arounduntil they are marked down or even until they decline to such a degreethat they must be discarded.

Such characteristics left hibiscus with the reputation that, despite themesmerizing beauty of the flowers, they were for collectors who had timeto attend to the seemingly exacting requirements of the plants. As aresult, while new varieties were produced by hobbyists yearly,propagation of modern hybrids on a commercial scale was generally rare.Common garden varieties (‘Seminole Pink’, ‘Brilliant’, ‘President’,‘Painted Lady’, ‘Butterfly’, ‘Lago’, for example), which are easy toroot, fast growing, and tolerant of a wide range of growing conditionswere the only hibiscus widely available. The “exotics” were of littleinterest to commercial growers.

Many new varieties of hibiscus representing a vast improvement inrosa-sinensis hybrids, have been produced by an intense hybridizingprogram conducted by the Inventor at his commercial nursery inPlaquemine, La. The objective of the program has been to producevarieties of hibiscus which root easily under commercial rootingconditions, grow well on their own roots, maturing rapidly intowell-leaved, salable plants under commercial greenhouse conditions.Further objectives are to produce hibiscus cultivars as aforementioned,having large-flowers with unique and desirable flower characteristics,such as size, color intensity and pattern.

Asexual reproduction of the new hibiscus by hardwood, semi-hardwood, andterminal cuttings taken in a controlled environment in Plaquemine, La.,has shown that the unique features of these new hibiscus are stable andreproduced true to type in successive generations.

SUMMARY OF THE INVENTION

The cultivar ‘DUP-BYR’ has not been observed under all possibleenvironmental variables. The phenotype may vary somewhat with variationsin environment such as temperature, light intensity, nutrient and waterstatus without, however, any variation in genotype. For example, duringcooler weather, flowers of many hibiscus cultivars may demonstrate anincreased intensity in pink tones. Furthermore, as with many varietiesof hibiscus, cooler weather can result in a decrease in flower diameter,and a corresponding reduction in size of sepals and pistil. Moreover, asindicated below, plant characteristics vary greatly with culture, withinternode spacings often increasing in warmer weather and with highersoil fixed nitrogen content. Plants grown at higher temperatures alsoexhibit a faster rate of growth. In general the plant used in thefollowing description was grown at temperatures which never dipped below55 F. Because the Inventor's one gallon pot plants are grown for anaverage time of about 5.5 to 6 months prior to sale, and the 10 inch potplants are grown for an average time of about 7 to 8 months prior tosale, it is difficult to provide a precise temperature profile requiredto give the average plant measurements described in the belowdescription. The growing period can encompass several seasons, withseasonal fluctuations in high/low temperatures as well as photo period.It is expected that the daily high temperature ranged from about 70 F toabout 95 F, and the daily low temperature, which never dipped below 55F, ranged from about 65 F to about 80 F.

The following traits have been repeatedly observed and are determined tobe the unique characteristics of ‘DUP-BYR.’ These characteristics incombination distinguish ‘DUP-BYR’ as a new and distinct cultivar.

-   -   1. Glossy, dark green leaves.    -   2. Extremely upright, sturdy growth habit, appropriate for        container production and culture.    -   3. Freely flowering habit.    -   4. A double flower having petals and petaloids having a body of        lavender blue, and a margin of rose-purple.    -   5. The plant is at least as free-flowering as each parent, and        has been found to root more easily under greenhouse conditions        than either parent.

BRIEF DESCRIPTION OF THE PHOTOGRAPH(S)

The accompanying colored photographs illustrate the overall appearanceof the new hibiscus, showing the colors as true as it is reasonablypossible to obtain in colored reproductions of this type.

Colors in the photographs may differ slightly from the color valuescited in the detailed botanical description which accurately describethe colors of the new hibiscus.

The photograph on the first sheet (FIG. 1) comprises a newly openedflower of ‘DUP-BYR’.

The photograph on the second sheet (FIG. 2) is an additional view of thebloom.

The photograph on the third sheet (FIG. 3) comprises a branch of oneplant in a ten inch container.

The photograph on the fourth sheet (FIG. 4) comprises a mature leaf.

DETAILED BOTANICAL DESCRIPTION

In the following description, color references are made to The RoyalHorticultural Society Colour Chart except where general terms ofordinary dictionary significance are used. The following observations,measurements, and values describe plants grown in Plaquemine, La., withone plant per 10 inch container. Plants used for the description wereabout 34 weeks old.

-   Botanical classification: Hibiscus rosa-sinensis.-   Propagation:    -   -   Type.—‘DUP-BYR’ has been propagated by taking hardwood,            semi-hardwood, and tip cuttings, with semi-hardwood            preferred. It should be noted that many methods of asexual            propagation, such as tissue culture and other cloning            processes, can be expected to show some degree of success in            the propagation of the present cultivar. However, of the            methods tried by the Inventor, the use of semi-hardwood            cutting has given the greatest yield of commercially salable            plants. Asexual propagation has resulted in plants which            have the flower and plant characteristics of the original            ‘DUP-BYR’ plant, and thus the variety is stable. Cuttings            from ‘DUP-BYR’ generally root well under commercial            greenhouse conditions. While greenhouse conditions such as            relative humidity and other factors such as cutting age            prior to planting affect the take, it is not unusual to get            a take of almost 100%. Please note that as successive            generations of cuttings are raised, the raiser may            experience a drop in take due to the virus infection,            particularly if at some point grafted plants are prepared,            and cuttings are taken from such a plant.        -   Time to initiate roots.—An average time of initiation at            approximately 22 C is approximately six weeks, with slightly            longer times during winter at comparable temperatures, and            slightly shorter times during summer at comparable            temperatures.        -   Time to develop roots.—An average time, at approximately 22            C, of development of a root system after initiation, is            approximately six weeks, with slightly longer times during            winter at comparable temperatures, and slightly shorter            times during summer at comparable temperatures. It should be            noted that root initiation and development can be affected            by greenhouse conditions, biological stressors such as            disease organisms, as well as environmental stressors such            as low or variant relative humidity, over- and under-            watering, temperature variations or high or low constant            temperatures. Thus, rooting times can be shorter or longer            than the times given above depending on the values of many            different characteristics during the rooting process known            in the art.        -   Root description.—Fibrous and well-branched.-   Plant description:    -   -   Plant form and growth habits.—Perennial evergreen having            exceedingly upright, sturdy growth which can be floppy if            not staked. As recognized by one of skill in the art,            internodal distance can be dependent upon greenhouse            temperature/time profile, fertilizer availability profile,            and other factors.        -   Branching habit.—Well branched, having approximately 3-4            laterals when a single stem plant is pinched back to a 5            inch height.        -   Plant height, soil level to top of flowers.—A salable plant            in a 10 inch nursery pot can be approximately 25 inches high            and 19 inches wide. Please note that cultural variables such            as those mentioned under “Plant form and growth habits,”            above, among others, can cause significant variation from            the values given herein.        -   Lateral branch description.—The average branch            characteristics of a salable plant grown as a 10 inch            nursery pot: Average Length: Approximately 14″. Average            Diameter: Approximately 0.5 cm measured at the transition            from green to woody stem texture. Texture: Immature: Smooth.            Mature: Woody and rough.-   Mature foliage description:    -   -   Arrangement.—Alternate, single, numerous, symmetrical.        -   Length.—Approximately 11.8 cm.        -   Width.—Approximately 8.2 cm.        -   Shape.—Ovate to cordate.        -   Apex.—Acute.        -   Margin.—Entire, broadly undulate.        -   Texture.—Glabrous, rugose.        -   Color.—Young foliage, upper surface: More green than 147A;            glossy. Mature foliage, upper surface: Generally darker than            147A; glossy.        -   Petiole.—Average Length: 2.4 cm. Average Diameter: 0.3 cm.            Texture: Fine pubescence on upper surface; lower surface,            glabrous. It should be noted that as with other plant growth            characteristics, foliage color and size can vary with            nutrient availability, greenhouse temperature, day length,            and other conditions of culture.-   Flower description:    -   -   Natural flowering season.—Year round, with number and size            reduction in extended periods of cold weather, such as            daytime temperatures of less than 60 C. Extreme heat can            slow growth and flower production.        -   Flower arrangement.—Flowers arranged singly at terminal leaf            axils. Very free-flowering, with usually 2-3 developing            flower buds per lateral branch, flowers generally hang            downward or face outward.        -   Flower appearance.—Medium-sized, mostly fully double with            occasional semi-double flowers. Flowers are open for one to            two days before senescence, which is often accompanied by            partial or full petal closure. Flowers persistent.        -   Flower diameter.—‘DUP-BYR’ flowers are generally in the            range of from about 5″ to 6.5″ when fully open, with largest            flowers produced during warm weather (for example, day and            night time temperatures above 73 F).        -   Flower depth.—Flower depth was measured to average            approximately 3.2 cm. Flower depth was measured after            removal of a petal and a sepal to expose the base of the            pistil. The measurement was taken on a fully opened flower            in the direction of the pistil, from the base of the ovaries            to the maximum height of the flower petal, i.e., the point            of recurvature of the petal. While double flowers comprise            extra petal tissue, the depth is measured by using the point            of recurvature of the outermost whorl of petals. It should            be noted that outermost whorl of hibiscus blossoms can            flatten out during the day, or increase or decrease in            curvature or degree of petal reflex during the day, and thus            variance from the foregoing value is possible.        -   Flower bud (just before showing color).—Rate of opening: 1-2            days. Rate of opening is generally faster in warmer weather.            Flower bud dimensions were measured on a bud which was            approximately one day from opening. Bud length was measured            from the tip of the bud to the abscission zone where bud and            peduncle meet. The average length of a bud which is one day            from opening is approximately 6.2 cm. Bud diameter was            measured at the widest part of the bud, an area            approximately halfway up the outside of the developing            petals. The average diameter of a bud which is one day from            opening is approximately 3.0 cm. It should be noted that bud            dimensions can vary somewhat with cultural conditions, and            variations can even be observed in buds which are at the            same stage of development. Furthermore, buds which develop            into fully double flowers are generally of greater diameter            than buds which develop into semi-double flowers. Shape:            Elliptical. Color of immature bud: More green than 147A.        -   Petals.—Texture: Smooth, satiny. Arrangement: The corolla            consists of five petals arranged in a whorl, having regular            partial overlap, even when the flower is fully open.            Doubling is present as a ruff of petal tissue formed due to            the mutation of anthers into petal tissue. The doubled            petals are thus attached to the staminal column and are            often distinct from the petals which comprise the corolla.            Shape of a petal from the outer whorl: Roughly spatulate,            with a rounded apex and a truncate base. The margin of each            petal is undulate and entire, the overlap of petals in the            outer whorl is minimal such that the flower margin resembles            a wind mill. A representative outer whorl petal length was            measured to be 8.9 cm, and was taken from the base of the            petal to the farthest point on the margin opposite the base.            A representative width is 7.9 cm, and was measured            perpendicularly to the pistil at the widest point of the            petal. Petal size can vary with cultural conditions, such as            temperature, and thus the flower size and shape can vary as            well. Often, flowers which are produced at colder            temperatures are smaller and appear more fully overlapped,            giving almost a wheel-shaped appearance. When fully open,            the outer whorl petals of ‘DUP-BYR’ flowers can be sharply            recurved. The color of a warm weather flower is described            below. It has been observed that variations in temperature            can effect the stronger or weaker expression of certain            pigments, changing the balance of color, and thus variations            in color intensity and pattern can occur with temperature.            In particular, the expression of pink pigments may increase            as growing temperatures drop into the sixties. It should be            noted that the colors of hibiscus are among the most            changeable of all flowers. A newly opening morning bloom            generally has the most intense coloration, but as the flower            flattens out and is exposed to the sun, many pigments begin            to fade immediately, resulting in a flower which can look            like a different variety altogether. The flower of ‘DUP-BYR’            when exposed to sunlight, can fade to a dull medium pink by            the second day. The first day morning colors are described            below. Color: Upper surface: Petals and petaloids have a            body of 97B, and a margin of N74D. Lower surface: N74D.        -   Sepals.—Unlike the petals, sepals are relatively invariant            in color. Their size can be affected by the same cultural            conditions which affect flower size. They are generally            smooth and elongated oblong with acute apices (pointed            tips). They are fused at the long edges into a cupped calyx            bearing at its brim the five pointed tips. When the petals            of the flower spread open, the five pointed tips, which are            flush with the backs of the opening petals, are forced into            a radiating five point star-shaped configuration, which can            be observed on the profile and reverse pictures. A            representative width, which is measured perpendicularly to            the long axis of the sepal at the position on the sepal at            which the oblong edges transition from fused to unfused, is            approximately 0.9 cm. A representative length, measured on            the sepal from the free point to the fused point is            approximately 2.5 cm. Color: Upper surface: Close to 146A.            Lower surface: Close to 147A.        -   Peduncle.—Length: 4.1 cm. Angle: Approximately 40 degrees            from branch. Strength: Strong, flexible. Texture: Smooth.        -   Reproductive organs.—Androecium: Stamen number:            Approximately 25-100. Anther shape: Crescent. Anther color:            11D. Amount of pollen: Moderate. Pollen color: 11A.            Gynoecium: Pistil number: 1. Pistil length (from base of            ovaries to top of stigma): 8.1 cm. Style length (from base            of ovaries to stigma branching point): 7.9 cm. Style            diameter, at base: 1.1 cm. Stigma number: varies, 0-5.            Stigma color: 32A.

It should be noted that the dimensions of a hibiscus blossom generallychange not only during bud development, but also during opening, as wellas during the life of the opened flower. For instance, upon opening, thepetals generally gain in length. Double varieties gain significant massduring opening. Furthermore, after opening, the pistil continues to growin length while the anther filaments which hold the pollen sacs increasein length, the pollen sacs open and the stigmas separate, each at thetip of a branched style structure. Toward the end of the flower life,possibly due to a reduction in turgor pressure, the pistil may shrink inlength and the petals may slightly decrease in area. Usually, thesenescing petals of the flower fold toward the pistil to some degree, insome cases, completely enfolding it.

Furthermore, the present variety ‘DUP-BYR’ is capable of producing arange of flower forms, from semidouble to full double. Because the“doubling” is usually due to the conversion of sexual flower segments,such as anther tissue, and less commonly, pistil and stigma tissue, topetal tissue, the degree of doubling has an effect on the number ofreproductive segments exhibited by such a flower. For example, a fullydouble flower can have a greatly reduced number of anthers with respectto a single flower. Even if the doubling has not effected the conversionof stigma tissue into petal tissue, the effect of doubling is often todeform the staminal column to such an extent that the stigma are buriedin petal or column tissue and are either under-developed or impossibleto locate, and in some cases, completely absent, with only the pointedstyle branches remaining as the flower's attempt to express its femaleflower segments. Another phenomenon which is observed in hibiscusflowers which exhibit a high degree of doubling is the occasionalproduction of multiple pistils, most often fused at the base or alongtheir lengths. Usually, such fusion results in pistils which areincomplete, but the potential for multiple pistils, and thussupernumerary anthers and stigmas exists with double hibiscus ingeneral, and the present variety, ‘DUP-BYR,’ in particular.

-   Disease resistance: ‘DUP-BYR’ has not been observed to be resistant    to pathogens common in hibiscus. However, it has been observed in    the green house to have a higher resistance to root rot than that of    many existing hybrid varieties grown on their own roots. If desired,    and if the risk of virus infection is of no concern, the present    variety can be grafted onto a rootstock and be grown as a grafted    plant.

1. A new and distinct hibiscus plant named ‘DUP-BYR’, either grafted oron its own roots, as illustrated and described.